disPlayList INTERFACE TECHNOLOGY For the creation of the Playlist Interface the following software is used :

Diagram showing the technical setup

The collaborating artists in the Playlist Network Project prepare their media as they are used to, using software tools like Final Cut Pro, Adobe Premiere and Cool Edit Pro. They catalog and share their media files by using CatDV Pro and synchronise with a shared catalog on the CatDV Server, hosted by Ryerson University. The artists use CatDV's ability to define custom user fields, by following the Playlist Interface metadata strategy.

Once the catalogue is ready to be interfaced, one of the artists exports the updated catalogue to XML, using the CatDV export function. The resulting file is than converted by a custom made program to fit the needs of the playlist interface. The document is now ready to be stored in Xindice, an XML database. An XML file containg the used keywords is also stored in the database. Besides the metadata, a .JPG file representing each clip is uploaded to the still folder on the webserver. These stills can be custom made, or generated by CatDV. The last step is for each artist to create a sure stream real media file of their media, using Helix DNA Producer, or other tools like Cleaner.

To view and navigate the artwork the web users must use the Internet Explorer web browser and have Real Player installed as well as the BS contact VRML player.


CatDV Pro
Tool for cataloging digital video


Open Source Relational Database

Apache Xindice
Open Source XML Database

Apache Tomcat
Open Source Java Enabled Webserver

Helix DNA
Open platform for digital media creation, delivery and playback

Internet Explorer
Web Browser

Real Player
Media Player

BS Contact VRML
VRML Player

The following technology was used to establish communication between the several layers:

Flowchart showing what happens at several levels of communication after a user selects a Clip

Different parts of the Playlist Interface talk to eachother using various technologies. At the clients side Javascript is used to perform a request to the server. At the server side a Java Servlet processes the request. It responds to the client by sending an XML stream. This XML is processed by JavaScript using the Microsoft DOM Object. Both JavaScript and VB Script are used to convert this XML to meaningful VRML instructions, creating dynamic visualisation, navigation and interaction in a 3D environment.

Besides VRML, JavaScript is also used to trigger RealPlayer. Not only does it instruct the player to play a certain file, it also polls the player in order to detect changes to visualise in the VRML environment.

In order to dynamically create playlists and synchronise the media a Java Servlet generates a multimedia presentation in the SMIL language. While SMIL tells RealPlayer what mediafiles when to play, Real Player and Helix Streaming Server negotiate how the media should be delivered. Since the media is encoded to support several target groups (sure stream), the Streaming Server will serve the optimal streams to the requesting client.


XML Java Real Media Sure Stream

HTML Java Script VB Script VRML SMIL

  The following sources were used for the creation of the server side software and dynamic media creation:

The server side software used for the Playlist Interface was extracted from the V2_ codebase of the DataCloud and Amicitia Public Web Acces Site projects.

disPlaylist Technology notes by Brigit Lichtnegger 2004

Amicitia PWA
DataCloud 2.5